In an existing gas appliance, a burner generally includes a bottom cup and a flame spray, and the flame spray is arranged on the bottom cup. The bottom cup defines a gas intake, and gas is sprayed towards an interior of the bottom cup through a nozzle after passing through the gas intake. The gas intake of the burner at present is fixed and unchangeable, cannot meet use requirements of different consumers, and is not high in universalization and standardization degree. Meanwhile, a design object of the burner pursued continuously by a global burner industry is to improve a thermal efficiency of the burner, optimize a design to improve a manufacturability of the burner, thereby facilitating processing and improving production and assembly efficiency of the burner.